Surgical stapling apparatus with firing lockout assembly

ABSTRACT

A surgical stapling apparatus includes a loading unit having first and second jaw members, a drive beam, and a firing lockout assembly. The drive beam is axially movable within the loading unit during a firing sequence. The firing sequence includes an advancement stroke which moves the first and second jaw members to an approximated position and a retraction stroke which moves the first and second jaw members to an unapproximated position. The firing lockout assembly includes an iterating plate, a capture gear, and a lockout pin. The iterating plate is disposed adjacent to the drive beam and is incrementally movable proximally within the loading unit during the firing sequence. The capture gear is rotatable between first and second positions during the firing sequence and is configured to move the iterating plate. The lockout pin is configured to lock the drive beam after a pre-determined number of firing sequences.

FIELD

This application generally relates to surgical stapling apparatus, and more particularly, to surgical stapling apparatus having a firing lockout assembly.

BACKGROUND

Surgical stapling apparatus for stapling tissue are well known in the art and typically include a handle assembly, a body portion extending distally from the handle assembly, and a tool assembly supported on a distal end of the body portion. The tool assembly includes first and second jaws which are movable in relation to each other between unapproximated and approximated positions. The first jaw supports an anvil assembly and the second jaw supports a cartridge assembly. The cartridge assembly includes a staple cartridge that houses a plurality of staples and can include a knife for severing tissue.

Some known surgical stapling apparatus are reposable, and a fired or spent staple cartridge can be replaced with an unfired or fresh staple cartridge to facilitate reuse of the surgical stapling apparatus. To prevent re-firing of a surgical stapling apparatus with a spent staple cartridge or to prevent firing of a surgical stapling apparatus which does not include a staple cartridge, it is known to provide a lockout mechanism which prevents advancement of a drive member of the surgical stapling apparatus. A lockout mechanism that prevents the use of the surgical stapling apparatus past its intended life cycle is desired.

SUMMARY

The surgical stapling apparatus of this disclosure includes a firing lockout assembly for preventing the use of the surgical stapling apparatus beyond its intended life cycle. The firing lockout assembly locks a drive assembly of the surgical stapling apparatus to prevent firing of the surgical stapling apparatus after a pre-determined number of firing strokes thereby improving patient safety by preventing the surgical stapling apparatus or component(s) thereof (e.g., a loading unit) from being re-processed or used beyond its intended number of uses. The firing lockout assembly is mechanical and designed to be in-line with and iterated by existing drive assemblies (with minimal modifications thereto), thereby providing a simple and cost-effective safety feature for surgical stapling apparatus.

In aspects of the disclosure, a loading unit for a surgical stapling apparatus includes first and second jaw members, a drive beam, and a firing lockout assembly. The drive beam is axially movable within the loading unit during a firing sequence. The firing sequence includes an advancement stroke which moves the first and second jaw members to an approximated position and a retraction stroke which moves the first and second jaw members to an unapproximated position. The firing lockout assembly includes an iterating plate, a capture gear, and a lockout pin. The iterating plate is disposed adjacent to the drive beam and is incrementally movable proximally within the loading unit during the firing sequence of the drive beam. The capture gear is rotatable between first and second positions during the firing sequence of the drive beam and is configured to move the iterating plate. The lockout pin is configured to lock the drive beam after a pre-determined number of firing sequences.

The firing lockout assembly may have an unlocked state in which the lockout pin is disengaged from the drive beam and a locked state in which the lockout pin is engaged with the drive beam. In some aspects, the drive beam defines a lockout hole therethrough and the lockout pin is aligned with the lockout hole. The iterating plate blocks the lockout hole from the lockout pin until the pre-determined number of firing sequences has been reached. In certain aspects, the iterating plate defines a lockout window therethrough. The lockout window is axially offset relative to the lockout hole when the firing lockout assembly is in the unlocked state and the lockout window is aligned with the lockout hole when the firing lockout assembly is in the locked state. In some aspects, the lockout pin is loaded against the iterating plate by a lockout spring when the firing lockout assembly is in the unlocked state.

The iterating plate may include first and second teeth disposed on opposed longitudinal edges thereof and the capture gear may include first and second legs configured to alternatively engage the first and second teeth of the iterating plate. In some aspects, the first and second teeth are longitudinally offset with respect to each other. In certain aspects, when the capture gear is in the first position, the first leg of the capture gear engages one of the first teeth of the iterating plate and, when the capture gear is in the second position, the second leg of the capture gear engages one of the second teeth of the iterating plate that is distal to the one of the first teeth.

The capture gear may define an opening therethrough, and the firing lockout assembly may further include a pivot pin extending through the opening. In some aspects, the pivot pin includes a cylindrical body and a rail extending longitudinally along the length of the cylindrical body. In certain aspects, the opening defined in the capture gear includes a circular portion configured to receive the cylindrical body of the pivot pin and a detent configured to receive the rail. The capture gear is rotatable about the pivot pin between the first position, in which the rail is disposed within a first portion of the detent, and the second position, in which the rail is disposed within a second portion of the detent.

The drive beam may include a projection extending outwardly therefrom, and the capture gear may include an arm having a finger configured to engage the projection during the firing sequence to rotate the capture gear between the first and second positions.

In aspects of the disclosure, a surgical stapling apparatus including a handle assembly, an elongate tubular body extending distally from the handle assembly, and a loading unit extending distally from the elongate tubular body. The loading unit includes first and second jaw members, a drive beam, and a firing lockout assembly. The drive beam is axially movable within the loading unit during a firing sequence. The firing sequence includes an advancement stroke which moves the first and second jaw members to an approximated position and a retraction stroke which moves the first and second jaw members to an unapproximated position. The firing lockout assembly includes an iterating plate, a capture gear, and a lockout pin. The iterating plate is disposed adjacent to the drive beam and is incrementally movable proximally within the loading unit during the firing sequence of the drive beam. The capture gear is rotatable between first and second positions during the firing sequence of the drive beam and is configured to move the iterating plate. The lockout pin is configured to lock the drive beam after a pre-determined number of firing sequences.

The first jaw member of the loading unit may include an anvil assembly and the second jaw member may include a staple cartridge assembly.

The firing lockout assembly of the loading unit may have an unlocked state in which the lockout pin is disengaged from the drive beam and a locked state in which the lockout pin is engaged with the drive beam. In some aspects, the drive beam defines a lockout hole therethrough and the lockout pin is aligned with the lockout hole. The iterating plate blocks the lockout hole from the lockout pin until the pre-determined number of firing sequences has been reached. In certain aspects, the iterating plate defines a lockout window therethrough. The lockout window is axially offset relative to the lockout hole when the firing lockout assembly is in the unlocked state and the lockout window is aligned with the lockout hole when the firing lockout assembly is in the locked state.

The iterating plate of the firing lockout assembly may include first and second teeth disposed on opposed longitudinal edges thereof and the capture gear of the firing lockout assembly may include first and second legs configured to alternatively engage the first and second teeth of the iterating plate.

The capture gear of the firing lockout assembly may define an opening therethrough, and the firing lockout assembly may further include a pivot pin extending through the opening.

The drive beam of the loading unit may include a projection extending outwardly therefrom, and the capture gear of the firing lockout assembly may include an arm having a finger configured to engage the projection during the firing sequence to rotate the capture gear between the first and second positions.

The details of one or more aspects of this disclosure are set forth in the accompanying drawings and the description below. Other aspects, as well as features, objects, and advantages of the aspects described in this disclosure will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

Various aspects of this disclosure are described hereinbelow with reference to the drawings, which are incorporated in and constitute a part of this specification, wherein:

FIG. 1 is a side, perspective view of a surgical device in accordance with an aspect of the disclosure;

FIG. 2 is a side, perspective view of a loading unit of the surgical device of FIG. 1 ;

FIG. 3 is a close-up view of the area of detail 3 indicated in FIG. 2 , showing a drive beam of a drive assembly, in an unactuated position, and a firing lockout assembly of the loading unit of FIG. 2 ;

FIG. 4 is a side, perspective view of the drive beam and the firing lockout assembly, with parts separated, of FIG. 3 ;

FIG. 5 is a close-up view of the area of detail 5 indicated in FIG. 4 , showing a pivot pin and a base of a capture gear of the firing lockout assembly;

FIG. 6 is a close-up view of the area of detail 6 indicated in FIG. 4 , showing an arm of the capture gear of the firing lockout assembly;

FIG. 7 is a side view of the drive beam and the firing lockout assembly of FIG. 3 , shown along section line 7-7 of FIG. 3 , during an advancement stroke of the surgical device of FIG. 1 ;

FIG. 8 is a close-up view of the area of detail 8 in FIG. 7 , showing a projection of the drive beam engaged with the arm of the capture gear of the firing lockout assembly;

FIG. 9 is a close-up view of the area of detail 9 in FIG. 7 , showing the pivot pin disposed within the capture gear of the firing lockout assembly when the capture gear is in a first position;

FIG. 10 is a cross-sectional view of the loading unit of FIG. 2 , taken along section line 10-10 of FIG. 7 , showing the firing lockout assembly in an unlocked state;

FIG. 11 is a side view of the drive beam and the firing lockout assembly of FIG. 7 , during a return stroke of the surgical device of FIG. 1 ;

FIG. 12 is a close-up view of the area of detail 12 in FIG. 11 , showing the projection of the drive beam engaged with the arm of the capture gear of the firing lockout assembly;

FIG. 13 is a close-up view of the area of detail 13 in FIG. 11 , showing the pivot pin disposed within the capture gear of the firing lockout assembly when the capture gear is in a second position;

FIG. 14 is a side view of the drive beam and the firing lockout assembly of FIG. 11 , during a subsequent firing stroke of the surgical device of FIG. 1 ; and

FIG. 15 is a cross-sectional view of the loading unit of FIG. 2 , showing the firing lockout assembly in a locked state.

DETAILED DESCRIPTION

Aspects of this disclosure are now described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. Throughout this description, the term “proximal” refers to a portion of a device, or component thereof, that is closer to a user during use of the device in its customary fashion, and the term “distal” refers to a portion of the device, or component thereof, that is farther from the user during use of the device in its customary fashion. Directional reference terms, such as “upper,” “upwardly,” “lower,” “downwardly,” “side,” and the like, are intended to ease description of the components in this disclosure and are not intended to have any limiting effect on the ultimate orientation of a device or any parts thereof.

Referring now to FIG. 1 , an exemplary surgical device or surgical stapling apparatus 1 is shown for use in stapling tissue in accordance with aspects of the disclosure. The surgical stapling apparatus 1 generally includes a handle assembly 10, an elongate tubular body 22 extending distally from the handle assembly 10, and a loading unit 30 extending distally from the elongate tubular body 22.

The surgical stapling apparatus 1 will further be described to the extent necessary to disclose aspects of the disclosure. For a detailed description of the structure and function of exemplary surgical devices, reference may be made to U.S. Pat. No. 10,426,468, the entire contents of which are incorporated herein by reference.

The handle assembly 10 includes a handle housing 12 that receives a power-pack (not shown) configured to power and control various operations of the surgical stapling apparatus 1, and a plurality of actuators 14 (e.g., finger-actuated control buttons, knobs, toggles, slides, interfaces, and the like) for activating various functions of the surgical stapling apparatus 1. The elongate tubular body 22 is a component of an adapter assembly 20 which further includes a knob housing 24. The knob housing 24 is configured for operable connection to the handle assembly 10 and the elongate tubular body 22 is configured for operable connection to the loading unit 30. Alternatively, the elongate tubular body 22 may be supported directly on the handle assembly 10 (e.g., permanently affixed to or integrally formed with the handle assembly).

The loading unit 30 is a disposable loading unit (“DLU”) that is releasably secured to the elongated tubular body 22 and thus, replaceable with a new loading unit 30. Alternatively, the loading unit 30 may be permanently affixed to the elongated tubular body 22. The loading unit 30 may be a multi-use loading unit (“MULU”) that is re-useable a predetermined number of times. For example, during a surgical procedure, the surgical stapling apparatus 1 can be used to staple and cut tissue, and a reload (e.g., a staple cartridge 54) of the MULU is replaced after each staple and cut operation of the surgical stapling apparatus 1 a pre-determined number of times before the entire MULU needs to be replaced.

FIGS. 1 and 2 illustrate the loading unit 30 which includes a housing portion 32, a tool or jaw assembly 34, and a mounting assembly 36 interconnecting the housing portion 32 and the tool assembly 34. Alternatively, the tool assembly 34 may be directly coupled to the housing portion 32. The loading unit 30 further includes a drive assembly 60 (FIG. 2 ) and a firing lockout assembly 70 disposed within the housing portion 32.

The loading unit 30 is substantially as described in U.S. Pat. No. 9,016,539 (“the '539 patent”) and U.S. Pat. No. 9,757,126 (“the '126 patent”), the entire contents of each of which are incorporated herein by reference, except that the firing lockout assembly 70 has been changed and the drive assembly 60 has additional features configured for use with the firing lockout assembly 70. Accordingly, the components of the loading unit 30 which are common to that which are disclosed in the '539 and '126 patents will be briefly described herein (reference may be made to the '539 and '126 patents for a more detailed description), and the changes to the drive assembly 60 and the firing lockout assembly 70 will be described in detail herein.

FIG. 2 illustrates the mounting assembly 36 which is secured to the tool assembly 34 and is pivotally coupled to the housing portion 32 to pivotally secure the tool assembly 34 to the housing portion 32. The tool assembly 34 includes first and second jaw members 34 a, 34 b, at least one of which is pivotable with respect to the other such that the tool assembly 34 is movable between an open or unapproximated position in which the first and second jaw members 34 a, 34 b are spaced apart with respect to each other, and a closed or approximated position in which the first and second jaw members 34 a, 34 b are substantially adjacent each other.

The first jaw member 34 a of the tool assembly 34 includes an anvil assembly 40 and the second jaw member 34 b of the tool assembly 34 includes a staple cartridge assembly 50. The anvil assembly 40 includes an anvil plate 42 and a cover plate 44 secured over the anvil plate 42. The anvil plate 42 has a tissue facing surface 46 including staple forming pockets (not shown) defined therein. The tissue facing surface 46 also defines a central longitudinal slot (not shown) extending substantially along the length of the anvil plate 42 to facilitate passage of a knife 66 (FIG. 4 ) of the drive assembly 60 therethrough.

The staple cartridge assembly 50 includes a cartridge carrier 52 and a staple cartridge 54 selectively received and supported within the cartridge carrier 52. The staple cartridge 54 may be removably and/or replaceably attached to the cartridge carrier 52 by, for example, a snap-fit connection, a detent, a latch, among other types of connectors within the purview of those skilled in the art. The staple cartridge 54 has a tissue facing surface 56 including staple pockets or retention slots 55 formed therein. Each of the staple pockets 55 houses a staple (not shown) therein. The tissue facing surface 56 further defines a central longitudinal slot 57 extending along a substantial length of the staple cartridge 54 to facilitate passage of the knife 66 (FIG. 4 ) of the drive assembly 60 therethrough.

FIGS. 3 and 4 illustrate the drive assembly 60 which includes an elongated drive beam 62 having an I-beam 64 disposed at a distal end thereof. The I-beam 64 includes a vertical or central strut 64 a interconnecting an upper or first beam 64 b and a lower or second beam 64 c. The knife 66 is defined in a distal face of the vertical strut 64 a. The vertical strut 64 a of the I-beam 64 is slidable between the anvil and staple cartridge assemblies 40, 50 (FIG. 2 , e.g., through the central longitudinal slots) with the first and second beams 64 b, 64 c of the I-beam 64, respectively, engaged with the anvil and staple cartridge assemblies 40, 50.

The drive beam 62 includes a proximal end (not shown) configured to releasably engage a firing rod (not shown) extending through the elongate tubular body 22 (FIG. 1 ) of the surgical stapling apparatus 1 such that during a firing stroke or sequence (which includes an advancement stroke and a retraction or return stroke) of the surgical stapling apparatus 1, the firing rod imparts axial movement to the drive beam 62. During actuation of the firing stroke, the drive beam 62 is advanced distally to drive or push the staples out of the staple pockets 55 (FIG. 2 ) of the staple cartridge 54 toward the anvil assembly 40 (FIG. 2 ) and to divide tissue disposed between the anvil and staple cartridge assemblies 40, 50. After the drive beam 62 is advanced, the drive beam 62 is retracted proximally back to its initial or unactuated position, as seen in FIG. 3 .

The drive assembly 60 further includes a projection 68 extending from the drive beam 62 that is configured to engage a finger 92 of a capture gear 82 of the firing lockout assembly 70 during distal advancement and proximal retraction of the drive beam 62 during a firing stroke. The projection 68 may be a peg, post, tab, or other protuberance within the purview of those skilled in the art. In aspects, the projection 68 extends transversely from an upper or first longitudinal edge 62 a of the drive beam 62. The drive beam 62 further includes a lockout hole 69 defined therethrough that is disposed distal to the projection 68 of the drive beam 62 and configured to receive a lockout pin 96 of the firing lockout assembly 70 after a pre-determined number of firing strokes of the surgical stapling apparatus 1 (FIG. 1 ).

The firing lockout assembly 70 includes a linear gear or iterating plate 72, a plate retainer 80, a capture gear 82, a pivot pin 94, a lockout pin 96, and a lockout spring 98. The iterating plate 72 is incrementally moved proximally during each firing stroke of the surgical stapling apparatus 1 (FIG. 1 ) to mechanically count the number of times the surgical stapling apparatus 1 is fired. After a pre-determined number of firing strokes, a lockout window 75 defined in the iterating plate 72 aligns with the lockout hole 69 defined in the drive beam 62 so that the lockout pin 96 can pass through the lockout window 75 and the lockout hole 69 in the drive beam 62 to lock the drive beam 62 and prevent further use of the loading unit 30.

The iterating plate 72 is positioned adjacent to a side surface 62 b of the drive beam 62 over which the projection 68 of the drive beam 62 extends. The iterating plate 72 includes an elongate body 74 having a proximal end portion 74 a coupled to the plate retainer 80 and a distal end portion 74 b defining the lockout window 75 therethrough. The plate retainer 80 is secured to the housing portion 32 of the loading unit 30 and maintains alignment of the iterating plate 72 relative to the drive beam 62. In some aspects, the plate retainer 80 is resilient (e.g., a spring) and, in other aspects, the plate retainer 80 undergoes permanent deformation (e.g., shortening) in response to proximal movement of the iterating plate 72. The lockout window 75 is sized and shaped to receive the lockout pin 96 therethrough.

The elongate body 74 of the iterating plate 72 includes an upper or first edge 74 c and a lower or second edge 74 d extending longitudinally along the length of the elongate body 74. First teeth 76 are positioned along the first edge 74 c and second teeth 78 are positioned along the second edge 74 d. The first and second teeth 76, 78 are longitudinally offset with respect to each other with successive first and second teeth 76, 78 paired together for use during a firing stroke of the surgical stapling apparatus 1 (FIG. 1 ). For example, a proximal first tooth 76 a is paired with a distal second tooth 78 a such that during a firing stroke, the capture gear 82 engages the proximal first tooth 76 a during distal advancement of the drive beam 62 and engages the distal second tooth 78 a during proximal retraction of the drive beam 62 to move the iterating plate 72 proximally within the housing portion 32 of the loading unit 30. Accordingly, the number of paired first and second teeth 76, 78 positioned along the iterating plate 72 correspond to a pre-determined number of firing strokes that the surgical stapling apparatus 1 (FIG. 1 ) may perform before the drive beam 62 is locked.

The capture gear 82 is pivotably supported within the housing portion 32 of the loading unit 30 and configured to actuate the iterating plate 72 relative to the drive beam 62. The capture gear 82 has a substantially c-shaped body 84 including a base 86 and two spaced legs 88 (first leg 88 a and second leg 88 b) extending distally from the base 86. The base 86 is configured to engage the pivot pin 94 and the first and second legs 88 a, 88 b are configured to respectively engage the first and second teeth 76, 78 of the iterating plate 72.

The base 86 of the capture gear 82 defines an opening 85 (FIG. 4 ) through which the pivot pin 94 extends. The pivot pin 94 is secured to the housing portion 32 of the loading unit 30 such that the capture gear 82 is pivotable about the pivot pin 94 relative to the housing portion 32. As seen in FIG. 5 , the pivot pin 94 includes a substantially cylindrical body 94 a having a longitudinal extending rail or ridge 94 b extending along the length thereof. The opening 85 defined in the base 86 of the capture gear 82 has a complementary geometry to the pivot pin 94 and includes a substantially circular portion 85 a configured to receive the body 94 a of the pivot pin 94 and a notch or detent 85 b configured to receive the rail 94 b of the pivot pin 94 therein. The capture gear 82 is pivotable about the pivot pin 94 between a first position, in which the rail 94 b of the pivot pin 94 is disposed within a first or proximal portion of the detent 85 b (FIG. 9 ), and a second position, in which the rail 94 b of the pivot pin 94 is disposed within a second or distal portion of the detent 85 b (FIG. 13 ). Thus, the detent 85 b limits the rotation of the capture gear 82.

FIGS. 3 and 4 illustrate the first and second legs 88 a, 88 b of the capture gear 82 which include toothed ends 88 c, 88 d that are configured to alternately engage the first and second teeth 76, 78 of the iterating plate 72. Specifically, when the capture gear 82 is in the first position, the toothed end 88 c of the first leg 88 a engages one of the first teeth 76 of the iterating plate 72 (FIG. 7 ) and, when the capture gear 82 is in the second position, the toothed end 88 d of the second leg 88 b engages one of the second teeth 78 of the iterating plate 72 (FIG. 11 ).

FIGS. 3, 4, and 6 illustrate the capture gear 82 which further includes an arm 90 extending upwardly and outwardly from the base 86. The arm 90 has a finger 92 extending transversely from an end of the arm 90 towards the drive beam 62 that is configured to engage the projection 68 of the drive beam 62. The arm 90 is flexible and the finger 92 is rigid such that when the finger 92 is contacted by the projection 68 during axial movement of the drive beam 62, during either the advancement or return stroke, the projection 68 contacts the finger 92 to rotate the capture gear 82 and flexes the arm 90 to enable passage of the projection 68 past the finger 92. It should be understood that the position of the arm 90 on the capture gear 82 and the projection 68 on the drive beam 62 may vary so long as the finger 92 aligns with the projection 68 and movement of the drive beam 62 enables rotation of the capture gear 82.

The lockout pin 96 is secured to the housing portion 32 of the loading unit 30 by the lockout spring 98. The lockout pin 96 includes a first end 96 a coupled to the lockout spring 98 which, in turn is coupled to the housing portion 32, and a second end 96 b positioned against the iterating plate 72. The lockout pin 94 is aligned with the lockout hole 69 of the drive beam 62 when the drive beam 62 is in the unactuated position (FIG. 3 ). The lockout pin 96 is loaded or tensioned against the iterating plate 72 by the lockout spring 98 until the iterating plate 72 is moved to a position in which the lockout window 75 aligns with the lockout hole 69 of the drive beam 62. In this position, the lockout spring 98 is free to move to its biased position and pushes the lockout pin 94 through the lockout window 75 and the lockout hole 69.

Referring now to FIGS. 7-10 , during a firing stroke of the surgical stapling apparatus 1 (FIG. 1 ), the drive beam 62 is initially advanced in the direction of arrows “A” in FIGS. 7 and 8 (e.g., distally) to approximate the first and second jaw members 34 a, 34 b (FIG. 2 ) and to staple and divide tissue disposed therebetween. As the drive beam 62 is advanced, the projection 68 on the drive beam 62 contacts the finger 92 of the capture gear 82, as seen in FIGS. 7 and 8 , thereby pivoting the capture gear 82 in a first direction indicated by arrow “B” (e.g., a distal or counter-clockwise direction) about the pivot pin 94 to the first position, as seen in FIG. 9 , in which the rail 94 b of the pivot pin 94 is disposed within the proximal portion of the detent 85 b of the capture gear 82. In this first position, the first leg 88 a of the capture gear 82 is engaged with one of the first teeth 76 of the iterating plate 72. The flexibility of the arm 90 of the capture gear 82 enables the drive beam 62 to continue its distal advancement past the capture gear 82 after the capture gear 82 is moved to the first position. As seen in FIG. 10 , the lockout pin 96 is loaded against the iterating plate 72 by the lockout spring 98 to maintain the firing lockout assembly 70 in an unlocked state thereby enabling continued use of the surgical stapling apparatus 1 (FIG. 1 ).

Turning now to FIGS. 11-13 , during the return stroke, the drive beam 62 is retracted in the direction of arrows “C” in FIGS. 11 and 12 (e.g., proximally) to unapproximate the first and second jaws 34 a, 34 b (FIG. 2 ) and release the stapled and divided tissue. As the drive beam 62 is retracted in the direction indicated by arrows “C” in FIGS. 11 and 12 , the projection 68 on the drive beam 62 contacts the finger 92 of the capture gear 82, as seen in FIGS. 11 and 12 , thereby pivoting the capture gear 82 in a second direction indicated by arrows “D” (e.g., proximal or clockwise direction) about the pivot pin 94 to the second position, as seen in FIG. 13 , in which the rail 94 b of the pivot pin 94 is disposed within the distal portion of the detent 85 b of the capture gear 82. In this second position, the second leg 88 b of the capture gear 82 is engaged with one of the second teeth 78 of the iterating plate 72 that is distal to the first tooth 76 that was previously engaged with the first leg 88 a during the advancement stroke, thereby moving the iterating plate 72 proximally such that the distance “y” between the lockout pin 96 and the lockout window 75 is less than the distance “x” (FIG. 7 ) between the lockout pin 96 and the lockout window 75 during the advancement stroke of the firing sequence.

Accordingly, each successive firing stroke, such as that shown in FIG. 14 , moves the iterating plate 72 proximally relative to the drive beam 62 and closes the distance between the lockout pin 96 and the lockout window 75. After a pre-determined number of firing strokes (corresponding to the number of pairs of first and second teeth 76, 78 of the iterating plate 72), the lockout pin 96 aligns with the lockout window 75 of the iterating plate 72, as shown in FIG. 15 . Once the lockout pin 96 is aligned with the lockout window 75, the lockout spring 98 is free to move to its biased position and passes the lockout pin 96 through the lockout window 75 as well as the lockout hole 69 of the drive beam 62 thereby preventing further use (e.g., firing) of the surgical stapling apparatus 1 (FIG. 1 ). Thus, in order to reuse the surgical stapling apparatus 1, the loading unit 30 must be replaced with a new loading unit 30.

While illustrated as being used in a hand-held powered surgical device hereinabove, it is contemplated, and within the scope of the disclosure for the firing lockout assembly to be configured for use with various mechanical, electromechanical, and/or electrosurgical instruments and systems. For example, the firing lockout assembly may be utilized in manual (e.g., non-motor driven) surgical devices, such as those shown and described in U.S. Pat. Nos. 5,865,361, 5,964,394, 7,128,253, and 7,334,717, the entire contents of each of which are incorporated herein by reference. As another example, the firing lockout assembly may be utilized in end effectors of robotic surgical systems, such as the robotic surgical system shown and described in U.S. Pat. No. 8,828,023, the entire contents of which are incorporated herein by reference.

While aspects of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. It is to be understood, therefore, that the disclosure is not limited to the precise aspects described, and that various other changes and modifications may be effected by one skilled in the art without departing from the scope or spirit of the disclosure. Therefore, the above description should not be construed as limiting, but merely as exemplifications of aspects of the disclosure and the subject matter of the disclosure is not limited by what has been particularly shown and described. Thus, the scope of the disclosure should be determined by the appended claims and their legal equivalents, rather than by the examples given. 

What is claimed is:
 1. A loading unit comprising: first and second jaw members movable between approximated and unapproximated positions; a drive beam axially movable within the loading unit during a firing sequence, the firing sequence including an advancement stroke which moves the first and second jaw members to the approximated position and a retraction stroke which moves the first and second jaw members to the unapproximated position; and a firing lockout assembly including: an iterating plate disposed adjacent to the drive beam, the iterating plate incrementally movable proximally within the loading unit during the firing sequence of the drive beam; a capture gear rotatable between first and second positions during the firing sequence of the drive beam, the capture gear configured to move the iterating plate; and a lockout pin configured to lock the drive beam after a pre-determined number of firing sequences.
 2. The loading unit according to claim 1, wherein the firing lockout assembly has an unlocked state in which the lockout pin is disengaged from the drive beam and a locked state in which the lockout pin is engaged with the drive beam.
 3. The loading unit according to claim 2, wherein the drive beam defines a lockout hole therethrough and the lockout pin is aligned with the lockout hole, the iterating plate blocking the lockout hole from the lockout pin until the pre-determined number of firing sequences has been reached.
 4. The loading unit according to claim 3, wherein the iterating plate defines a lockout window therethrough, the lockout window axially offset relative to the lockout hole when the firing lockout assembly is in the unlocked state and the lockout window aligned with the lockout hole when the firing lockout assembly is in the locked state.
 5. The loading unit according to claim 2, wherein the lockout pin is loaded against the iterating plate by a lockout spring when the firing lockout assembly is in the unlocked state.
 6. The loading unit according to claim 1, wherein the iterating plate has first and second teeth disposed on opposed longitudinal edges thereof and the capture gear includes first and second legs configured to alternatively engage the first and second teeth of the iterating plate.
 7. The loading unit according to claim 6, wherein the first and second teeth are longitudinally offset with respect to each other.
 8. The loading unit according to claim 7, wherein, when the capture gear is in the first position, the first leg of the capture gear engages one of the first teeth of the iterating plate and, when the capture gear is in the second position, the second leg of the capture gear engages one of the second teeth of the iterating plate that is distal to the one of the first teeth.
 9. The loading unit according to claim 1, wherein the capture gear defines an opening therethrough, and the firing lockout assembly further includes a pivot pin extending through the opening.
 10. The loading unit according to claim 9, wherein the pivot pin includes a cylindrical body and a rail extending longitudinally along the length of the cylindrical body.
 11. The loading unit according to claim 10, wherein the opening defined in the capture gear includes a circular portion configured to receive the cylindrical body of the pivot pin and a detent configured to receive the rail, the capture gear rotatable about the pivot pin between the first position, in which the rail is disposed within a first portion of the detent, and the second position, in which the rail is disposed within a second portion of the detent.
 12. The loading unit according to claim 1, wherein the drive beam includes a projection extending outwardly therefrom, and the capture gear includes an arm having a finger configured to engage the projection during the firing sequence to rotate the capture gear between the first and second positions.
 13. A surgical stapling apparatus comprising: a handle assembly; an elongate tubular body extending distally from the handle assembly; and a loading unit extending distally from the elongate tubular body, the loading unit including: first and second jaw members movable between approximated and unapproximated positions; a drive beam axially movable within the loading unit during a firing sequence, the firing sequence including an advancement stroke which moves the first and second jaw members to the approximated position and a retraction stroke which moves the first and second jaw members to the unapproximated position; and a firing lockout assembly including: an iterating plate disposed adjacent to the drive beam, the iterating plate incrementally movable proximally within the loading unit during the firing sequence of the drive beam; a capture gear rotatable between first and second positions during the firing sequence of the drive beam, the capture gear configured to move the iterating plate; and a lockout pin configured to lock the drive beam after a pre-determined number of firing sequences.
 14. The surgical stapling apparatus according to claim 13, wherein the first jaw member of the loading unit includes an anvil assembly and the second jaw member includes a staple cartridge assembly.
 15. The surgical stapling apparatus according to claim 13, wherein the firing lockout assembly of the loading unit has an unlocked state in which the lockout pin is disengaged from the drive beam and a locked state in which the lockout pin is engaged with the drive beam.
 16. The surgical stapling apparatus according to claim 15, wherein the drive beam defines a lockout hole therethrough and the lockout pin is aligned with the lockout hole, the iterating plate blocking the lockout hole from the lockout pin until the pre-determined number of firing sequences has been reached.
 17. The surgical stapling apparatus according to claim 16, wherein the iterating plate defines a lockout window therethrough, the lockout window axially offset relative to the lockout hole when the firing lockout assembly is in the unlocked state and the lockout window aligned with the lockout hole when the firing lockout assembly is in the locked state.
 18. The surgical stapling apparatus according to claim 13, wherein the iterating plate of the firing lockout assembly has first and second teeth disposed on opposed longitudinal edges thereof and the capture gear of the firing lockout assembly includes first and second legs configured to alternatively engage the first and second teeth of the iterating plate.
 19. The surgical stapling apparatus according to claim 13, wherein the capture gear of the firing lockout assembly defines an opening therethrough, and the firing lockout assembly further includes a pivot pin extending through the opening.
 20. The surgical stapling apparatus according to claim 13, wherein the drive beam of the loading unit includes a projection extending outwardly therefrom, and the capture gear of the firing lockout assembly includes an arm having a finger configured to engage the projection during the firing sequence to rotate the capture gear between the first and second positions. 